// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.

#ifndef STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
#define STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_

#include "port/port.h"
#include "port/thread_annotations.h"

namespace leveldb
{

    // Helper class that locks a mutex on construction and unlocks the mutex when
    // the destructor of the MutexLock object is invoked.
    //
    // Typical usage:
    //
    //   void MyClass::MyMethod() {
    //     MutexLock l(&mu_);       // mu_ is an instance variable
    //     ... some complex code, possibly with multiple return paths ...
    //   }

    class SCOPED_LOCKABLE MutexLock
    {
    public:
        explicit MutexLock(port::Mutex *mu) EXCLUSIVE_LOCK_FUNCTION(mu) : mu_(mu)
        {
            this->mu_->Lock();
        }
        ~MutexLock() UNLOCK_FUNCTION() { this->mu_->Unlock(); }

        MutexLock(const MutexLock &) = delete;
        MutexLock &operator=(const MutexLock &) = delete;

    private:
        port::Mutex *const mu_;
    };

} // namespace leveldb

#endif // STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
